A survey of the physical, working conditions of twelve operating submarines was completed. The purpose was to determine the range of conditions normally encountered in sonar shacks. These conditions will next be assessed for their effects on performance and comfort so that optimum conditions can be specified. The results showed a great diversity of illumination, both in color and quantity, on the various sonar systems. Effective levels of illumination are generally considerably higher under blue light than under red. While the duty-cycle of six hours on and 12 hours off watch was standard, rotation periods during watch varied. Several conditions within the sonar shack could be changed to improve working conditions.